A stroke may be an example of a serious life-threatening medical condition and may require urgent medical attention, ischemic stroke is one example of a condition that has a limited time window in which a clinician should make a treatment decision. The sooner a patient receives correct treatment the less damage they may be likely to sustain. In this limited time window, decisions may need to be made quickly if brain tissue is to be saved.
Typically, a non-contrast CT scan (NCCT) may be performed as a first time in stroke diagnosis. The NCCT scan results may be used to exclude hemorrhagic stroke as a cause. The NCCT scan results may be used to exclude conditions that mimic the symptoms of stroke, for example seizure and bran tumor. Conditions that mimic the symptoms of stoke may be described as stroke mimics. The NCCT scan results may be used to identify dense vessels (whist may be indicative of a dot) and/or to identify ischemia.
A subsequent CT angiography (CTA) that combines a CT scan with an injection of a contrast medium may be performed to confirm an initial diagnosis and/or to gain more information to aid a treatment decision.
The CTA scan may allow a review of the NCCT scan. For example, features identified in the NCCT scan may be reviewed in the CTA scan. A number of scenarios may occur CTA review. For example, the CTA review may be used to visualize filling defects in vessels to confirm dense vessels that were seen in the NCCT scan but were considered to be dubious or questionable in the NCCT scan. A search for a blockage may be undertaken, for example to review a vasculature supplying a particular region which is ischemic according to the NCCT. The CTA review may be used to review collateral circulation in potential mechanical thrombectomy candidates. The CTA review may be used to determine recanalization success in follow up treatment.
Some stroke imaging leaders advise a NCCT scan followed by a CTA scan as a minimum level of care acute ischemic stroke.
Recent clinical trials have demonstrated, a positive impact on acute ischemic stroke of endovascular therapy and mechanical therapy. As a result, strode management guidelines have been updated to incorporate endovascular therapy, with an emphasis on the importance of imaging. However, expert reading may not be not guaranteed in all clinical centers and/or at all times of day. For example, an on-call radiologist may not specialize in neurological imaging.
Performing a first and second scan and analysing the results second scan may be time-consuming for a medical practitioner. Given the time-sensitive nature of stroke condition, a length of, time taken to review the scan data may in some circumstances have an impact on a clinical outcome. The level of experience of the medical practitioner performing the scan n arriving at the treatment decision may vary. The urgent nature of the condition may in some circumstances lead to incorrect treatment decisions and/or preventable damage occurring.